Various information appliances exist that enable customers to be provided with information content. The customers may be mobile, traveling from location to location and utilizing multiple information appliances, such as in the case of a traveling salesperson. Such information appliances include televisions, portable computers and automobile navigational aids, among others. In a conventional system, the information appliance connects to an access node of a network of interconnected servers that are in turn connected to multimedia servers that provide information content. Using an information appliance, a mobile customer is able to download multimedia information content to review news, movies, radio, books and other files containing information of various types and formats. Typically, however, a mobile customer's review of the requested/desired information content is delayed until an entire file or a substantial portion of a file is received at the information appliance. This delay may be significant, as the information appliance may need to access remotely located information content providers via a vast network of interconnected servers. In addition, packet loss during transmission can result in reception of low-quality versions of real-time information content that is to be presented to the mobile customer. Moreover, delay and packet loss are magnified as transmission distance increases and as the number of interconnected servers that are interacted with along the transmission path increases.
In order to reduce delay and packet loss during reception of information content, some information appliances and networks provide cache memories. A cache provides a place to store information more or less temporarily, saving time and reducing the burden of re-obtaining the stored information from a remote location via the network. For example, a web page that has been requested by a conventional web browser is stored in the browser's cache directory on the hard disk of the information appliance. That way, when the mobile customer returns to a recently viewed page, the browser can obtain the web page from the cache rather than the original server, thereby saving time and reducing network traffic.
In the same manner, caching can be implemented on a network by distributing information content to multiple cache servers from which most users would obtain information and by periodically refreshing the information content stored at each cache server. The cache server is located relatively close to information appliances and typically within an enterprise that saves information content that server users have requested so that successive requests for previously requested information content can be satisfied by the cache server rather than requiring an extended use of the network. The cache server not only serves its users by obtaining information more quickly but also reduces network traffic. Thus, a cache server improves the speed and the reliability of the delivery of information content, providing a higher quality of service because information content is not transmitted via congested networks.
Conventional cache systems for mobile customers, however, suffer various deficiencies similar to those described above for non-cache systems. First, content stored in an information appliance at one location may not be available in an information appliance at another location. Second, content stored in a cache at one location may not be stored in a cache at another site. As a result, the mobile customer may be required to wait for information content to download from a remote information content provider. Such an arrangement may also cause the mobile customer to receive a low-quality version of the desired information content. Worse yet, the mobile customer may not be able to access the desired information content. These deficiencies are exacerbated by the mobile customers' need for information at specific locations and times.